Defending champion Sloane Stephens is the sole remaining top-six seed left in the women's singles at the US Open after a day of upsets at Flushing Meadows. Wimbledon champion Angelique Kerber and fifth seed Petra Kvitova both fell on Louis Armstrong Stadium, which is rapidly establishing itself as a graveyard of champions, while sixth seed Caroline Garcia also lost 7-5, 4-6, 6-7 (7/4) to Carla Navarro. Kerber was dumped by Dominika Cibulkova 3-6, 6-3, 6-3.

Kvitova was the last victim of the day, the two-time Wimbledon champion overpowered by the hottest player of the moment: Aryna Sabalenka, 20, who won 7-5, 6-1. The Belarusian was not ranked highly enough to get into the tournament 12 months ago but has soared into the top 20 and won her first WTA Tour title in New Haven on the eve of the tournament.